Comparison of corneal topographic measurements and high order aberrations in keratoconus and normal eyes

The aim of this report was to compare corneal topographic measurements and anterior high order corneal aberrations in eyes with keratoconus and normal eyes by using Scheimpflug-Placido topography.

Eighty cases diagnosed with mild (group 1), moderate (group 2), and advanced (group 3) stage keratoconus (KC) according to Amsler-Krumeich Classification and 81 healthy (control group) cases were retrospectively examined. The mean keratometric measurements (as both diopters (Kavg) and mm values (mmavg)), central corneal thickness values (CCT), high order aberration (HOA), total wavefront aberration (TWA), coma, trefoil, and spherical aberration measurements were performed using Sirius topography equipment. The topographic values were compared between the groups.

There were 25 cases in group 1 KC (15.5%), 34 cases in group 2 KC (21.1%), 21 cases in group 3 KC (13.1%), and 81 cases (50.3%) in the control group. In terms of mean age and gender distributions, there was no statistically significant difference between the groups (p>0.05). However, there was significant difference between the groups in terms of Kavg, CCT, HOA, TWA, coma, trefoil, and spherical aberration values (p<0.01). Mean HOA, TWA, coma, trefoil, and spherical aberration values were observed to increase with the severity of KC disease.

Anterior high order corneal aberrations were significantly increased in eyes with moderate and advanced keratoconus. Anterior high order corneal aberration measurements are a useful tool to guide the physician in diagnosis and classification of keratoconus.